Respiratory resting and/or therapy using a respiratory gas circuit or device typically requires, opening, closing, and/or isolating various breathing/respiratory gas paths. Traditional balloon technologies, used for these functions, are bulky and have a resistance to inflation due to elasticity. As a result, the traditional balloon technologies are very slow to inflate and deflate, and also cause high airflow resistance when deflated.
Butterfly valves or shutter-type valves are also utilized in respiratory testing. However, butterfly valves often exhibit leakage rates which render some respiratory measurement unreliable. Moreover, butterfly valves require electromechanical actuation which can be bulky and impractical to implement.
The drawings referred to in this description should be understood as not being drawn to scale except if specifically noted.